Friction coupling



Jan. 1 5, 1935. J. BING FRICTION COUPLING Filed Feb; 11, 1951 Jgd/6 Mya I@ 6 @MM5 '20 place toc late toy'be able to prevent the burning compression spring 18, so that the friction sur- 20 40 4 shows diagrammatically a bimetallic thermowhere the coupling is used' in rooms in which 40 4,5 2, while the armature 4 (iO-Operating With the vthe heating of an easily fusible solder, in which 45 Patented Jan. l5,Y 1935 UNITED STATES' PMENT OFFICE 1,988,413 n FRIcTIoN cpUPLING Julius Bing, Berlin, Germany, assignor to Magnet- Werke G. m.b. H., Eisenach, Germany, a. company of Germany Application February 11, 1931, Serial No. 515,117

In Germany February 15, 1930 13 claim. (c1. 19a-15o) With friction couplings, in particular those for the armature disc against the magnet body. In large outputs, there exists the defect that with the flange part 7 is inserted a metallic pressure long continued heavy over-loading the friction vessel 10. In the present case the vessel is screwed surfaces burn in consequence of the slipping un in from the outside, in such manner that the inder heavy pressure which occurs under this conner surface of the vessel, consisting preferably of 5 dition, if the couplingis not quickly disengaged. good conducting metal as for example copper, is Slipping which continues only for short periods, level with the friction surface 8. The air space such as is caused by small variations of output of the vessel is closed by a diaphragm 11 carryor loading, or the slower sliding of the friction ing a small contact plate 12 which can come into surfaces due to negligible overloading is generally contact with an adjustable contact screw 13, 10 `permissible for relieving the driving gear of load when the diaphragm 11, in consequence of the variations, and is also of little harm to the fricexpansion caused by heating of the air enclosed tion surfaces if these are correctly dimensioned. in the vessel, moves outwards. In this manner, a On the other hand, any long continued heavy current circuit is completed through branch wire l5 overloading must be avoided in order tqfspare the 27, wires 28, brushes li and slip rings 22a to relay 15 friction surfaces. This condition ispsatisfied at 15 which interrupts the energizing current suppresent by disengaging the coupling by hand. As plied to the winding 2 by way of switch 29. The such cverloads, however, frequently occur sudarmature disc is thereupon released by the magdenly, the disengagement by hand' often takes net body, and is moved along the shaft 5 by a of the friction surfaces. faces part from each other and the coupling is The invention provides means, which automatidisengaged. cally disengages the coupling, actuated by the The apparatus may be easily adjusted for any heatdeveloped by the slipping of the friction surdesiredperiod of heating', so that it is possible faces. For example, in the case of electromagto permit minor power or load variations of short 25 netic couplings, such means preferably comprises duration without automatic disengagement of a thermostat or the like'in the direct vicinity of the coupling taking place, while overloads lastthe friction surfaces, and actuating an electrical ing longer, which would damage the friction contact connected with a circuit containing a resurfaces by overheating, effect a rapid disengagelay which interrupts the current circuit energizment of the coupling.- 30 ing the coupling. I As the vessel 10 is completely sealed, so that The attached drawing illustrates by way of exthe contents thereof cannot escape, the action ample embodiments of the invention applied to may be adapted for sensitiveness by adding small friction couplings actuated .eleetromasnetically quantities of liquids of various boiling points to Fig. 1 shows a partial axial section through such the vessel. For example, by the use of carbon 35 a coupling, having disengaging means actuated disulphide, sulphuric ether or the like, a disenlya Pressure VeSSel- Figs- 2 and 3 ShOW diagramgagement of the coupling may be attained at matically two different electrical circuits with temperatures even below 50. This is, under cerdisengaging means actuated by fusible plugs. Fig. tain circumstances, of great importance in cases element serving as disengaging means. Y inflammable substances are dealt with.

Oil the Shaft 1, which may be regarded as the\ With electromagnetic couplings, a diaphragm driving ShaftfS keyed, aS ShOWn in Fig- 1, the vessel can be dispensed with and a direct switchcoupling body 3 Containing the magnet winding ing off of the magnet winding can be effected by magnet body is fixed on the driven shaft 5 in a contact is held, as shown in Figs. 2 and 3. such manner that it can shift in the axial direc- 1n the embodiment shown in Fig. 2, a plug 19, tion but cannot rotate relatively thereto. The readily fusible by heat, is located at the friction friction hrung indicated by 6, is in the present surface 8 in a conductive body 29 mounted in an case fitted on the armature disc 4, and engages insulating sleeve 3`0 in the nange 7 of coupling 50 with the metallic friction surface 8 provided on member 3. Energizing current for the magnet, the oppositely situated flange part 7 of the magcoil 2 is led from wire 17 through wire 27, one of net body 3, when energizing current supplied from the brushes 9, one of the slip rings 22 and wire the power supply wires 16, 17 through branch 31 to the conductive body 29 and plug 19, which wires 26, 27, brushes 9, and slip rings 22, draws holds a contact 20. From the contact 20 current 56 passes by way of the loose wire 32 to a terminal 33 and thence to the magnet coil 2. One end of a coil spring 21 abuts the head of contact 20, and the other end of the spring abuts an inner insulating sleeve 34, While the terminal 33 is mounted in an insulating plug 35. On the melting of the solder, the contact 20 is released and by action of the spring 21 is urged within the sleeve 34, so that interruption of the current supply to the energizing coil of the coupling is effected. As, according to the composition of the solder, the most diverse melting points can be obtained, this arrangement can also be easily suited to varied conditions.

Instead of the current interruption by means of this arrangement, a short circuit between the two slip rings through which the current supply to the coupling passes, may be produced as shown in Fig. 3. In this modified arrangement current is led to the magnet coil 2 through safety fuses 25 interposed in branch wires 26, 27. The heat sensitive device is of similar construction to that shown in Figure 2, except that the inner insulating sleeve 34 andthe loose wire 32 are omitted. The contact 23 is thus alwaysin connection with the conductive body 29 through spring 21, and only in electrical connection with terminal 24 when the plug 19 fuses and releases the contact 23. Current then passes from one slip ring 22 to the other through body 29, spring 21, contact 23, and terminal 24, shortcircuiting the magnet coil 2. The safety fuses 25 therefore operate, causing the energizing coil to lose current and the coupling to be disengaged.

Instead of the heat created by the slipping of the friction surfaces actuating the disengaging means by expansion of air in a pressure vessel, it can be utilized in a different manner for disengaging the coupling. For example, in Fig. 4 a bi-metallic thermo-element 36 of known construction is used, which, as soon as the heating reaches a definite value, becomes so distorted that it makes Contact with a terminal 3'?, and through the wires 38, 39 actuates the relay 15 or equivalent in the same manner as the pressure vessel, thereby shutting off the current energizing the coil 2.

The heat-sensitive device does not need to be tted directly on the friction surfaces of the coupling. It can be tted at some other position, provided that the place in question undergoes a sufficiently rapid increase of temperature on the slipping of the friction clutch surfaces, in consequence of the heat thereby produced. The arrangement shown in Fig. 1 is particularly advantageous, since it is actuated not only by the heat transmitted to it by conduction, but by the direct heating of the metallic bottom of the "essel 10 exposed to the slipping of the friction willich.

It will be obvious that the pressure vessel, bimetallic thermostat, and fuses referred to are equivalent means for making or breaking an electric circuit on rise of temperature of the friction surfaces of the coupling, and any one of them may be used with any of the means shown and idescribed for de-energizing of the magnet winding on the said circuit making or breaking means being caused to function.

These arrangements save the use of relays andA simplify the construction of such automaticallydisengaged couplings, so that they are particularly adapted for small couplings which must be produced cheaply.

I claim:-

1. A friction coupling comprising a driving body, a coaxially-disposed driven body, means for maintaining the bodies in frictional engagement, means for separating the bodies, and means for automatically releasing the engaging means and thereby enabling automatic operation of the separating means in the event of heating of the frictionsurfaces of the bodies due to slipping.

2. A friction coupling comprising a driving body and a driven body mounted for rotation with coaxially-disposed driving and driven shafts, means for maintaining the bodies in frictional engagement, means for separating the bodies, temperature sensitive means associated with one of the bodies, and means controlled by the sensitive means for releasing the engaging means and thereby enabling automatic operation of the separating means in the event of heating of the friction surfaces of the bodies due to slipping.

3. A friction coupling comprising a driving body and a driven body mounted for rotation with coaxially-disposed driving and driven shafts, means for maintaining the bodies' in frictional engagement, means for separating the bodies, a pressure vessel associated with one of the bodies, and means operable by the heating of the pressure vessel due to slipping of the friction surfaces of the bodies for releasing the engaging means and thereby enabling automatic operation Iof the separating means. v

4. A friction coupling comprising a driving body and a driven body mounted for rotation with coaxially-disposed driving and driven shafts, means for maintaining the bodies in frictional engagement, means for separating the bodies, a fuse associated with one of the bodies and adapted to melt in the event of heating due to slipping of their surfaces, and means controlled by the fuse for releasing the engaging means and thereby enabling automatic operation of the separating means.

5. A friction coupling comprising a driving body and a driven body mounted for rotation with coaxially-disposed driving and driven shafts, means for maintaining the bodies in frictional engagement, means for separating the bodies, a thermostat associated with one of the bodies and infiuenced by heating due to slipping of their surfaces, and a circuit controlled by the thermostat for releasing the engaging means and thereby enabling automatic operation of the separating means.

6. A friction coupling comprising a driving body, a driven body, electromagnetic means for maintaining the bodies in frictional engagement, temperature sensitive means associated with one of the bodies, and means controlled by the temperature sensitive means for releasing the electromagnetic engaging means in the event of heating of the friction surfaces of the bodies due to slipping.

7. A friction coupling comprising a driving body, a driven body, electromagnetic means for maintaining the bodies in frictional engagement, a pressure vessel associated with one of the bodies, and means operable by the heating of the pressure vessel due to slipping of the friction surfaces of the bodies for releasing the electromagnetic engaging means.

8. A friction coupling comprising a driving body, a driven body, electromagnetic means for maintaining the bodies inlfrictional engagement, a fuse associated with one of the bodies and adapted to melt in the event of heating duc to slippingoftheirsurfacesandmeanscontrolled by the fuse for releasing the electromagnetic ensesins means.

9. A friction coupling comprising a driving boib", a driven body, electromagnetic means for maintaining the bodies in frictional engagement, a thermostat associated with one of the bodies and iniiuenced by heating due to slipping of their surfaces, and a circuit controlled by the thermostat, for releasing the electromagnetic Vengaging means.

10. In a friction coupling having a driving body. a driven body, and electromagnetic meansf for maintaining said bodies in frictional engagement, means for autmnatically eii'ecting disengagement on heating of the friction surfaces by slipping of said surfaces, said means comprising an enclosed. pressure vessel associated with one ot the bodies, an electricrelay circuit, an electric contact associated with the vessel for closing the relay circuit at a temperature of the vessei, and areiay eonnectedwith the relaycircuit .for electing the de of the electromagnieummumbypmormomasmd means comprising a thermo-element associated with one of the bodies and adapted when subjected 'tor/a predetermined temperature rise to short the supply circuit, whereby the safety device is operated to de-energize said circuit.

12. -In a friction coupling having a driving body,

a driven body, and electromagnetic means for' maintaining said bodies in frictional engagement, means for automatically effecting disengagement on heating of the friction surfaces by slipping of said surfaces, said means comprising an enclosed pressure vessel associated with one of the bodies and having a liquid of known vaporization temperature therein, a pressure-controlled member enclosing said liquid, an electric relay circuit, an

electric contact connected with said member for closing the relay ciruit on the vaporization of the liquid, and a relay connected with the relay circuit, ior effecting the de-energizing of the electromagnetic means. Y

13. In a friction coupling having a driving body,` a driven body, and electromagnetic means for maintaining said bodies in irictional engagement',l means ior automatically eiiectng disengagement on the heating of the friction surfaces by slipping of said surfaces. said means comprising; a heat-sensitive device associated with one oi the bodies, an eiectric relay circuit, an electric contact associated with the said device for closing the relay circuit at a predetermined temperatime otthesaidsurface,andarelayconnectedwiththe relay circuit for eifecting the de-energizing of the electromagnetic means.

JULIUS BING. 

